1. Technical Field
The present invention relates to a fluid container containing fluid, a remanufacturing method of a fluid container by refilling a used fluid contained with fluid, and a sealing method of a fluid container.
2. Related Art
As a liquid container, an ink cartridge removably mounted in an inkjet printer (hereinafter, referred to as a printer), which is a type of liquid ejection apparatus, for example, is known. The ink cartridge has a container body with a substantially flat box-like shape. An ink chamber is defined in the container body to receive ink, which is liquid. An ink inlet hole is formed in a lower surface of the container body to allow initial filling of the ink into the ink chamber. An ink supply hole is also provided in the lower surface of the container body to receive an ink supply needle with the ink cartridge secured to the printer. To suppress leakage of the ink from the ink inlet hole and the ink supply hole, a cover film is bonded to the lower surface of the container body in such a manner as to seal the ink inlet hole and the ink supply hole.
After the ink cartridge is mounted in the printer, the printer consumes the ink through printing. This reduces the amount of the ink retained in the ink chamber until the ink cartridge becomes completely empty. The used ink cartridge is replaced by a new ink cartridge. The container body of the used ink cartridge is still usable for multiple cycles after the ink cartridge is removed from the printer. As disclosed in Japanese Registered Utility Model No. 3118670, a used ink cartridge may be remanufactured as a reusable ink cartridge by refilling the container body of the ink cartridge with ink. Such technique addresses to efficient use of resources and preservation of environments.
According to the technique of the above utility model, a bore is formed in the cover film at a position corresponding to the ink inlet hole using a piercing jig, before the used ink cartridge is refilled with ink. Then, a syringe, for example, is inserted into the ink inlet hole through the bore in the cover film to introduce the ink refill into the container body. Another film (a seal film) is then mounted on the cover film to close the bore and heated to be bonded to the cover film having the bore. In this manner, the bore is sealed and the ink is prevented from leaking from the bore.
A typical cover film is a laminated film formed by a thermally meltable bonding layer film and a surface layer film. The melting temperature of the surface layer film is higher than the melting temperature of the bonding layer film and has an enhanced heat resistance compared to the bonding layer film. The bonding layer film is mounted on the container body while held in contact with the container body and heated in this state. This bonds the bonding layer film to the container body. To remanufacture the used ink cartridge, the ink refill is introduced into the container body through the bore formed in the cover film. Afterwards, the seal film is mounted on the cover film. Like the cover film, the seal film is a laminated film formed by a thermally meltable bonding layer film and a surface layer film, which melts at a temperature higher than the melting temperature of the bonding layer film and has higher heat resistance than the bonding layer film. The bonding layer film of the seal film is placed on the surface layer film of the cover film while held in contact with the surface layer film of the cover film. In this state, the seal film is heated.
However, such heating of the seal film melts the bonding layer film of the seal film but does not melt the surface layer film of the cover film, which is maintained in contact with the bonding layer film of the seal film. It is thus likely that the seal film is not firmly bonded to the cover film. If bonding between the cover film and the seal film is insecure, a gap may be formed between the cover film and the seal film. The gap may allow leakage of the ink from the interior of the ink cartridge through the bore of the cover film.